In the downhole industry, valves are a common part of a system. Valves come in a variety of configurations; all intended to control the flow of fluid in one direction or another. One such configuration is known in the vernacular as a flapper valve. Such valves generally open to fluid flow in one direction (for example downhole direction) while closing to flow in an opposite direction (for example an uphole direction). Most commonly flapper valves are a part of a commercial product known as a safety valve, which allows an operator to maintain a flow passage only while an external input is maintained on the valve. For example, the valve may be a hydraulically operated valve that stays open as long as hydraulic pressure is supplied thereto through a hydraulic control line. The flapper will automatically close in the event that the hydraulic pressure is released. Such valves are very effective for their intended purposes.
Construction of safety valves is undertaken by utilizing a number of individual components and fastening them to one another to build the final product. In order to produce a commercially acceptable product, special threads with tight tolerances have been used to provide for sealing at one or more of the connection sites to prevent fluid migration therethrough. One such connection site is the interface between a flapper seat and a spring housing. Because special threads are expensive and require extra care during manufacture, a lower cost alternative at such interfaces would be welcomed by the art.